The assurance of an adequate gasket seal in the assembling of components is a source of problems in many industries. In many instances, the problems can be directly traced to the location of the gasket seal, the difficulty of maintaining the gasket in place during the assembling procedure and the difficulty of determining thereafter whether or not the gasket has remained in place during assembly. Many times a gasket is installed early in the assembly procedure and there is no simple or quick means to assure the adequacy of the seal until substantial additional assembly has occurred. Improper installation of such gaskets can result in significant material and time losses.
In one typical gasket seal arrangement, a gasket is fitted into a receptacle, race or groove of a first component and a second component is connected to the first component such that the gasket acts as a seal therebetween. When the gasket is properly installed and the components properly assembled the seal arrangement is very adequate for a wide variety of applications. Especially in assembly operations where the gasket is round, oval or rectangular in cross section, it is not infrequent that a gasket may be improperly installed so that it is twisted, or, that during the assembly of components the properly installed gasket becomes twisted so that the seal becomes defective for the purpose intended.
Much of the time an improper installation is unnoticed by the installer because of a difficulty in detection. A twisted gasket may not be readily visible, particularly on an assembly line where the speed of accomplishing a task is of primary importance. Further, some assembly procedures can cause the gasket to twist because of unusual strains placed upon the gasket, which twisting is not typically readily visible and apparent to the assembler.
In the automotive heat exchanger industry, plastic header tanks are typically assembled around the periphery of a metal radiator header sheet. The assembly is such that the metal header sheet typically comprises a gasket accepting slot or recess about its periphery, an elastomeric gasket is inserted into the slot or recess and the foot of the plastic header tank rests on the gasket. The plastic header tank is typically forced into the gasket bearing slot during assembly, deflecting the gasket a desired proportion of its undeflected height, and the header tank is retained in the slot. Because of the configuration of various retaining means, it may further be desirable for the gasket to be placed nearer the inner or outer wall of the gasket accepting slot or recess or at a controlled intermediate position between the inner and outer walls. During assembly it is not unusual for the elastomeric gasket to become twisted and because of the visual difficulty of seeing within the slot during assembly, such twisted gaskets may go undetected until testing of the completely assembled heat exchanger.
One object of this invention is to provide a means for increasing the detectability of twisted gaskets during assembly of gasket sealed components.
Another object of this invention is to provide a novel gasket having twist detection means.
A further object of this invention is to provide a novel gasket with gasket placement means.
A still further object is to provide a method for determining whether a gasket has twisted during installation or assembly.
These and other objects are achieved by the invention described as follows: